Electrolyte for surface treatment of metal implant and method for surface treatment of metal implant using said electrolyte

Abstract

An electrolyte for surface treatment of a metal implant includes 10-30 wt % of a sulfur-containing compound aqueous solution, 3-10 wt % of a phosphorous-containing compound aqueous solution, 0.5-2 wt % of an oxidant aqueous solution, and 0.5-5 wt % of a surfactant aqueous solution, with the rest being water. The concentration of the sulfur-containing compound aqueous solution is 0.1-3 M. The concentration of the phosphorous-containing compound aqueous solution is 0.05-2 M. The concentration of the oxidant aqueous solution is 0.05-1 M. The concentration of the surfactant aqueous solution is 0.05-5 M. The electrolyte is utilized for treating a surface of a metal implant, forming a porous oxide layer on the surface of the metal implant.

What is claimed is: 
     
       1. A method for surface treatment of a metal implant, comprising:
 cleaning a metal implant by sonication, with the metal implant being immersed in a solvent, until dirt adhered on a surface of the metal implant is removed; 
 connecting the cleaned metal implant to an anode and immersing the cleaned metal implant and a cathode in an electrolyte; and 
 supplying a voltage of 150-500 V to the anode and the cathode under a temperature of 0 to −10° C. to conduct a micro-arc discharge reaction on the metal implant in the electrolyte, until a porous oxide layer is formed on the surface of the metal implant, wherein the electrolyte comprises: 
 10-30 wt % of a sulfur-containing compound aqueous solution, 3-10 wt % of a phosphorous-containing compound aqueous solution, 0.5-2 wt % of an oxidant aqueous solution, and 0.5-5 wt % of a surfactant aqueous solution, with the rest being water; 
 wherein the sulfur-containing compound aqueous solution has a concentration of 0.1-3 M, the phosphorous-containing compound aqueous solution has a concentration of 0.05-2 M, the oxidant aqueous solution has a concentration of 0.05-1 M, and the surfactant aqueous solution has a concentration of 0.05-5 M. 
 
     
     
       2. The method for surface treatment of the metal implant as claimed in  claim 1 , wherein the porous oxide layer has a thickness of 0.5-30 μm, a pore diameter of 0.5-15 μm, and a pore deepness of 0.5-3 μm. 
     
     
       3. The method for surface treatment of the metal implant as claimed in  claim 1 , further comprising conducting the micro-arc discharge reaction for 10-60 minutes on the metal implant in the electrolyte, to form the porous oxide layer on the surface of the metal implant. 
     
     
       4. The method for surface treatment of the metal implant as claimed in  claim 1 , further comprising immersing the metal implant having the porous oxide layer in a weak acid solution under a temperature of 15-30° C. for 10-30 minutes after the porous oxide layer is formed, wherein the weak acid solution has a pH value of 5.0-7.0. 
     
     
       5. The method for surface treatment of the metal implant as claimed in  claim 4 , wherein the weak acid solution is a solution of oxalic acid, citric acid, lactic acid, formic acid or carbonic acid.